Constituents from Dendrobium aphyllum : Bibenzyls, furfurals, phenanthrenes, and phenylpropanoids and their antioxidant and anti-inflammatory potentials

Chemical investigation on the aqueous extract of Dendrobium aphyllum led to the isolation of thirty-one constituents with structures identified by analysis of the extensive spectroscopic data (1D/2D NMR, MS, UV, and ECD), including previously undescribed two bibenzyls, one furfural, and one phenolic acid, namely trigonopol D ( 1 ), trigonopol C ( 2 ), dendrofunan A ( 10 ), and 6-(4-hydroxy-3-methoxyphenyl)-3,6-dioxohexyl acetate ( 30 ), respectively, as well as twenty-seven known ones. Among them, there were one new natural product ( 11 ), seven compounds ( 6–7, 9, 12, 20, 28, 31 ) described from the genus Dendrobium for the first time, and fifteen compounds ( 8, 13–17, 19, 21–27, 29 ) isolated from D. aphyllum for the first time. Further, the antioxidant and anti-inflammatory potentials of fifteen compounds ( 4 – 5, 8, 11 – 12, 14 – 19, 22, 24, 26, and 29 ) with significant scavenging capacities against DPPH and hydroxyl radicals, and virtual docking activities inhibiting COX-2 and 5-LOX, respectively. Our study may draw the attention of medicinal plant taxonomists and supply potential quality markers for discrimination of D. aphyllum from other species in Dendrobium genus.